Why the Classic Windows PDF Patcher Is Now Open‑Source: Features, Tech Stack, and License

Overview

PDFPatcher (PDF补丁丁) is a Windows‑only utility for comprehensive PDF manipulation. It provides functions such as editing document properties (metadata, page size, page numbers), managing bookmarks (edit, auto‑generate), extracting content (lossless image extraction), inspecting PDF structure, creating new PDFs, splitting/merging files, and converting PDFs to other formats.

Open‑source release

After more than a decade of closed‑source distribution, the author released the source code on GitHub in early 2023 (third‑party components excluded). Repository URL: https://github.com/wmjordan/PDFPatcher. Within a month the repository received over 3,200 stars and active issue discussions.

Implementation details

Primary languages: C# for the .NET UI layer and C for native components.

Target framework: .NET Framework (Windows desktop) running on Windows 10.

Key third‑party libraries: iTextSharp (a .NET PDF library) and MuPDF (a C‑based PDF engine) compiled as a native DLL.

Build requirements

To compile the project you need:

Operating system: Windows 10.

IDE: Visual Studio 2019.

Workloads: “.NET desktop development” and “C++ desktop development” with the Windows 10 SDK.

The repository also includes a diagram of the source‑code structure to help developers navigate the solution.

License

The project is released under a custom “Conscience License”. In addition to the usual open‑source permissions, it adds two moral obligations:

Users who benefit from the software should perform a good deed.

If a derivative product generates profit, at least 0.1 % of the earnings must be donated to disadvantaged groups.